Activists raise San Onofre spent-fuel concerns

The pools that house spent nuclear fuel-rods at the San Onofre nuclear plant are too full, and plant operators should move the rods into dry storage casks as soon as possible, a nuclear industry consultant warns in a new report for an environmental group.

The report also offers an independent assessment of the amount of waste stored at San Onofre, which the author says was gleaned largely from Nuclear Regulatory Commission documents – 1,631 metric tons of spent fuel, nearly 1,100 tons stored in two pools meant to allow the material to cool before being placed in dry storage.

The consultant, Robert Alvarez, a Clinton-era senior adviser to the secretary of energy, also warns of what might be considered a low-probability but still possible hazard: a large earthquake causing a crack in a pool, causing water to drain, fuel rods to burn and lethal radioactive contamination to be released into the atmosphere.

"The bottom line as I see it is, it's not advisable to keep this stuff in pools for any long period of time," said Alvarez, who wrote the report for the group, Friends of the Earth, which successfully opposed a plan to restart one of San Onofre's sidelined reactors.

A spokeswoman for plant operator Southern California Edison declined to comment on the group's report, saying only that the NRC recently reaffirmed the safety of spent-fuel pools.

But the reactors had been offline since January 2012. That was when a small leak of radioactive gas prompted the shutdown of the plant's Unit 3 reactor. The other reactor, Unit 2, was already offline for routine maintenance.

Inspections revealed unexpected wear among thousands of metal tubes in the plant's four steam generators, two for each reactor. The wear was traced to design flaws in the generators, built by Mitsubishi Heavy Industries in Japan and installed in a $671 million operation between 2009 and early 2011.

Edison is preparing to move San Onofre into its decommissioning phase, which could take many years to complete.

"San Onofre's entire mission is transformed," Alvarez said. "It is now a major radioactive-waste storage site."

He said he is urging Edison to expedite transfer to dry storage from the spent-fuel pools because dry casks are safer.

"Those spent fuel pools are holding four to five times more than the original design intended," Alvarez said.

If a dry cask were somehow breached, it would still release "about 2,500 less radioactivity into the atmosphere than a spent-fuel pool fire."